Heretofore, for example, when a pressure fluid is exhausted from a fluid pressure device such as a valve or the like, exhaust noises tend to be generated, and therefore, a silencer has been disposed at the exhaust side of the fluid pressure device for minimizing such exhaust noises.
In such a silencer, as disclosed in Japanese Laid-Open Patent Publication No. 2001-289167, a cylindrically shaped filter is provided for removing moisture, dust and the like contained within the pressure fluid exhausted from the fluid pressure device, as well as for reducing exhaust noises, wherein both ends of the filter are retained respectively. In addition, by causing the pressure fluid that is exhausted from the fluid pressure device to be exhausted to the outside through the filter, exhaust noises of the pressure fluid device are reduced, and moreover, dust and the like contained within the pressure fluid is removed.
However, in the aforementioned silencer, when the pressure fluid is caused to flow toward the silencer from the fluid pressure device, the pressure drops precipitously in the vicinity of a connection part between the silencer and the fluid pressure device where the pressure fluid is released to atmosphere, and further, the temperature inside the silencer drops as a result of adiabatic expansion of the pressure fluid. Accordingly, owing to the reduction in temperature, moisture that is contained within the pressure fluid condenses in the vicinity of the connection part, and at the reduced temperature, such condensation becomes frozen at the interior of the silencer, resulting in a concern that operations of the fluid pressure device connected to the silencer may be adversely affected.
Further, in the case that the filtering capability of the filter is raised, with the aim of further reducing pressure fluid exhaust noises, clogging can easily be generated as a result of dust contained within the pressure fluid, with the problem that a desired noise reduction effect may not be obtainable.